Combustor for turbine of aircraft starter



Nov. 5, 1957 c. D. FLANlGE-N A COMBUSTOR FOR TURBINE OF AIRCRAFT STARTERFiled Nov. 24, 1953 2 Sheets-Sheet 1 FIG. 1

INVENTORS CAMERON D. PLAN/GE N ROBERT W/ED/S H7TOAE/VE) Nov. 5, 1957 c.D. FLANIGEN T 2,811,332

' COMBUSTOR FOR TURBINE OF AIRCRAFT STARTER Filed Nov. 24, 1955 2Sheets-Sheet 2 FIG. 2

IN V EN TORS 30 CAMERONDLFLAN/GEN k ROBERT W/ED/S Unite States Patentfiice Patented Nov. 5, 1957 COMBUSTOR FOR TURBINE OF AIRCRAFT STARTERCameron D. Flanigen, Hohokus, and Robert Wiedis, Maywood, N. J.,assignors to Bendix Aviation Corporation, Teterboro, N. J., acorporation of Delaware Application November 24, 1953, Serial N 0.394,038

3 Claims. (Cl. 60--39.65)

The present invention relates to improvements in means for effecting theignition and combustion of fuel in the combustion chamber of an air-fuelturbine type combustion starter such as disclosed and claimed in thecopending application Serial No. 328,988, filed December 31, 1952, byCameron D. Flanigen and William J. Dietz, Jr., now U. S. Patent No.2,742,759, and assigned to Bendix Aviation Corporation, assignee of thepresent application.

More particularly an object of the invention is to provide novel meanswhereby high turbulence is induced in a combustion chamber so as toassure high burning efficiency and a high heat release per unit volumewith a stoichiometric fuel air mixture.

Another object of the invention is to provide a combustion chamberhaving a fuel spraying nozzle mounted in a shield around which annularair inlet openings are provided for the admission of high velocity air,and down-stream of the annular air inlet openings is fitted a turbulatorplate, the purpose of which is to provide a plurality of individual airstreams directed into the main combustion chamber so as to assure thatupstream air inlet channel conditions do not adversely affect the airflow by directing more air into one portion of the combustion chamberthan another.

Another object of the invention is to provide a turbulator plate in thecombustion chamber so arranged as to direct high velocity air into thecombustion chamber in a swirling manner so as to isolate the mainburning in the combustion chamber into a portion of the chamber remotefrom the spark plug and fuel nozzle, and in so doing prolong the servicelife of these components.

The above and other objects and features of the invention will appearmore fully hereinafter from a consideration of the following descriptiontaken in connection with the accompanying drawings wherein oneembodiment of the invention is illustrated by way of example.

In the drawings:

Figure 1 is a longitudinal sectional view of a device embodying theinvention.

Figure 2 is an end view of Figure 1 illustrating the mounting of thefuel nozzle shield in the annular air inlet opening.

Figure 3 is a fragmentary plan view of the turbulator plate illustratingthe oppositely directed louvers of the turbulator plate.

Figure 4 is a fragmentary sectional view of a louver of the tubulatorplate showing the structure thereof. Referring to the drawing of Figure1, a starter drive section is indicated generally by the numeral 1 andmay be of the type disclosed in the aforenoted copending applicationSerial No. 328,988, now U. S. Patent No 2,742,759, including as shown bydotted lines in Figure 1 a turbine 2 connected through a shaft 3 andsuitable gearing to a starter jaw of conventional type. The starter jawis adapted to be connected to the engine to be started in a conventionalmanner. Details of the turbine 2, reduction gearing and starter jaw havebeen omitted as the structure thereof forms no part of the presentinvention.

The device embodying the subject invention may be formed in twoseparable casing parts, indicated by numerals 5 and 6, secured togetherby bolts 7 and including in the casing part 6 a part of shallowbowl-shaped combustion chamber 8. The flared annular casing part 6 hasprovided therein an end plate 6A in which are formed stator nozzles 9 atthe periphery for directing the exhaust gases from the chamber 8 so asto drive the turbine 2.

A source of compressed air is connected by a conduit 10 indicated bydotted lines to a high velocity air inlet cylindrical conduit 11 openinginto the sharply-flared part of the casing part 5. The air inlet conduit11 forming a part of the funnel-shaped casing part 5 has a frustoconicalair shield 12 mounted therein by legs 13, as shown in Figure 2, andbetween which legs suitable air openings 14 permit the high velocity airin conduit 11 to flow along the shield 12. The cone-shaped shield 12extends longitudinally in the air inlet conduit 11 and has an internalopening or cavity 15, a closed upstream end 16 and an open downstreamopening 17.

A fuel nozzle 18 is positioned in the closed end 16 of the air shield 12and arranged so as to spray fuel through the internal opening 15 and outthe open downstream end 17 into the combustion chamber 8, as shown byFigure 1. The fuel nozzle 18 is connected through a suitable passage 21formed in one of the legs 13 of the casing part 5 and connected byconduit 22, indicated by dotted lines and leading to a suitable sourceof fuel under pressure.

A spark plug or ignitor 24 projects into the internal opening 15adjacent the open end in the shield 12 to ignite the mixture of fuelspray and air which is in turn ejected into the combustion chamber 8through the open end 17 of the shield 12. The ignitor 24 is electricallyconnected by conductor 26 and 27 in a suitable energizing circuit, suchas shown and described for example in the aforenoted application SerialNo. 328,988, now U. S. Patent No. 2,742,759.

As shown in Figure 1, downstream of the air inlet openings 14 in conduit11, there is provided a sharplyflared turbulator plate indicatedgenerally by the numeral 30 mounted in spaced relation to the innersurfaces of the casing parts 5 and 6 and secured at its peripheral edgebetween the casing parts 5 and 6. The truncated conical plate 30 isfurther positioned at an annular inner edge 34 in a seat 35 formed inthe end 17 of the air shield 12.

The turbulator plate 30 is formed of a suitable high temperatureresistant material and, as shown by Figure 3, has provided therein threeconcentric rings of openings 36, 37 and 38. As shown specifically byFigure 4, the openings 36, 37 and 38 are each constructed so as to forma small pocket-like louvre. These louvres 36, 37 and 38 direct the highvelocity air stream from the openings 14 in a plurality of individualair stream along the inner circumferential surface of the plate in thedirection of the center line of their respective rings into the maincombustion volume in the chamber 8. It is to be noted from Fig. 3 thatlouvres of each ring are relatively closely-spaced so that there is asmall circumferential surface in front of the openings extending to theclosed back of the next louvre.

The louvre openings 36, 37 and 38 direct the air from the annularinclined air supply passage at a side 40 of the turbulator plate 30 in aswirling manner into the main combustion chamber 8 at the opposite side42 of the plate 30.

The intermediate ring of louvres 37 direct the air 3' in an oppositedirection to that of the inner and outer rings of louvres 36 and 38 soas to produce a greater degree of swirling turbulence in the combustionof the stoichiometric: fuel-aim mixture: and thereby; assure. that:upstream echannela conditions do notadversely affectthe p lug 24 and.fuel- -nozzle.18 so as.-.to decrease the wear thereon and therebyprolong the service life of the spark The.nozzles 9.- formedin-thetcasing plate 6A direct the exhaust gases from the combustionchamber 8 so to? drive at-suitable-turbine 2 cooperating therewith forstarting an engine',- as explained in the aforenoted application SerialNo. 328 988,' now Patent No. 2,742,759.

In operation itwill-.beeseen that the fuel is sprayedor-ejected into(the chamberB' throughthe end 17 of the air shield 12 by. fuel. nozzle18 and is ignited by the spark plug; 24 within" the frusto-iconical airshield 12 which serves toshield the fuel nozzle 18 and ignitor 24 fromthe high velocityair which is-admitted to the combustion chamber v 8 ina high swirl downstream of the fuel nozzle l8 and-ignitor-24'through'the louvres 36, 37 and 38 of the turbulator plate'30.

This arrangement thus provides for the subsequent burning of the ignitedfuel in a'location of the combustion chamber'8 relatively .-rernote'-from both the spark plug 24 and the fuel nozzle 18*so. as'to extend theservice life thereof.

The applicants novel arrangement provides for ready ignition; highburningefficiency, .extremely high heat release per' cubic. inch of:chamber volume and for burningat 'stoichio'metrimfuel air.ratio with-noexcess air.

Although. only-one'embodime'nt of the invention has been illustrated anddescribed, various changes in the formand-relativearrangementsof.the;p.arts may bemade to suit requirements.

What-is-claimed is:

1. A compact combustor for providi'nggaseszto a turbine'of a starter for:an .aircraft jetzen'ginecomprised of asharply-fiare'd; truncatedconical'turbulator plate 'having a. radially-outer largecircular ed'geEand radially inner. small circular edgeywallumeans extending fromsaidlargev edge to the outer? edgerof a' circular nozzle end plate:

having. a diameter somewhat-largerrthan the diameter of said largecircular1 edge;-;said--turbulatr plate; said wall means; and said endplateffdrmingza shallow bowl-shaped combustion chamber; said end platehaving atplurality.

of nozzles in the'rperipheral partthereof; said turbulator plate'havinga pluralityof concentric ringsaof equi-spaced' small,pocket-likelouvres-projecting into, and having .an opening into; saidcombustion'chamber; said pocket-like:

louvres of each" of said'rings being constructed and arranged so asto-direct .air circumferentially along the' inner surface of said;turbulator plate in thedirection ofthe circle line of their respectiverings; said louvres being so spaced that there is' ashort-circumferential surface, in

front of 'the louvre'opening; extending to theback of the next louvre ofeach zring; ;the louvres of at least one ring;

beingiarrangedtoidirect 'air: oppositely to the'direction of anadjacentring .of'clouvres so as to'provide turbulence; wallstructure closing'olfthe: opening of the radiallyinner small circular edge of saidsharply-flared turbulator plate; said-wallstructure having .a.fuel spraynozzle and an ighiterwprojectingjherefrorrl; outer/wall meanssubstantially uniformly: spacedaoutwardly from said turbu-- passage forair moving to said louvres; said annulari air supplyl assage Bein'g treeor: arwstrueture therein': im-

parting direction to the air moving to said louvres; and meanssurrounding a portion of said outer wall'structure and arranged to passair uniformly to said annular air supply passage.

2. A compact combustor for providing gases to a turbine of a starter foran aircraft jet engine comprised of a funnel-shaped casing part having agenerally-cylindrical rear section 'and asharply fiared conical forwardsection which terminates in forward annular edge portion; a shortflared: annular casing parthaving a rearward edge. portion extending.forwardly and radially-outward from the forward edge-portionof saidfunnel-shaped'casing part; said short flared casing part terminating ina forward annularedge'portion'with a circular opening which has adiameter somewhat larger than the forward end of said conical section ofsaid funnel-shaped casing part;

' a nozzle end plate extending across the circular opening of said shortflaredannular part; said nozzle end plate having a pluralityof nozzlesin the peripheral part thereof; a cone-shaped member axially-positionedin the interior of the generally-cylindrical rear section of saidfunnel-shaped casing part; said'eone-shaped member having a closedrearward upstream end and an open forward downstream end whichterminates at the transverse plane of the rear part of thesharply-flared section of said funnel-shaped casing part whereby annularair inlet passage means are provided around said cone-shaped member; asharply-flared, truncated conical turbulator plate having. aradially-outer, large circular edge and a radially-inner, smallcircular. edge; saidturbulatorplate extending from the open forward endof said cone-shaped memberto the rearward edge portion of said annularcasing part; said turbulator plate, said annular casing part and saidnozzle plate being so proportioned and arranged that ashallowbowl-shaped combustion chamber is formed; said sharply-flared turbulatorplate being spaced from the.

sharply-flared forward section of said funnel-shaped casing part toprovide. an'annular inclined air supply passage; the radially-outercircular edge of said turbulator plate being positioned and securedbetween the rearward edge portion .of said short flared vcasing part andthe forward edge portion of said funnel-shaped casing part by meanssecuring. these portions together; the annular inner edge of saidplatebeing. positioned in a seat formed;in theforward end of .saidfrusto-conical member; a fuel nozzle.

axially mounted in the closed'end of said cone-shaped member andarranged to spray fuel into said shallow bowl-shaped.combustion chamber;an ignition device extending into the interior of said cone-shapedmember adjacent-its open forward end; said turbulator plate having. aplurality of concentric rings of equi-spaced small,- pocket-like louvresprojecting into, and having an opening into, said combustion chamber;said louvres of each of said rings being constructed and arranged so asto' direct air circumferentially along the inner surface of saidturbulator plate in the direction of the center line of their respectiverings; said louvres being so spaced that there is a shortcircumferential surface in frontof the louvre opening, extending to theback of the next louvre of veach ring; the louvres of at least one ringbeingarranged to direct air oppositely to the direction of anadjacentringof louvres so as to provide turbulence; and said annular air supplypassage being free of structure for imparting direction to the airmoving to said louvres.

3. A compact combustor for providing gases to a turbine of a starter foran aircraft jet engine comprised of a sharply-flared, truncated conicalturbulator plate havinga radially-outer large circular edge and radiallyinner small circular edge; wall means extending from said large edgeto-the outer edge of a circular nozzle end plate. having-a diametersomewhat larger than the diarn eter of said. large circular edge; saidturbulator plate,- said' wall means and'said end. plate forming ashallowbowleshapecombt1sti0nrchamber; said end :plate having;

r a plurality 'ofi nozzles-in the peripheral vpart :thereof; saidivturbulator plate having a plurality of concentric rings of equi-spacedsmall, pocket-like louvres projecting into, and having an opening into,said combustion chamber; said pocket-like louvres of each of said ringsbeing constructed and arranged so as to direct air circumferentiallyalong the inner surface of said turbulator plate in the direction of thecircle line of their respective rings; said louvres being so spaced thatthere is a short circumferential surface, in front of the louvreopening, extending to the back of the next louvre of each ring; thelouvres of at least one ring being arranged to direct air oppositely tothe direction of an adjacent ring of louvres so as to provideturbulence; wall structure closing off the opening of the radially-innersmall circular edge of said sharplyflared turbulator plate; said wallstructure having a fuel spray nozzle and an igniter projectingtherefrom; outer wall means substantially uniformly spaced outwardlyfrom said turbulator plate to provide an annular inclined air supplypassage for air moving to said louvres; said annular air supply passagebeing free of any structure therein imparting direction to the airmoving to said louvres; and means surrounding said Wall structure andarranged to pass air uniformly to said annular air supply passage.

References Cited in the file of this patent UNITED STATES PATENTS2,531,810 Fyffe NOV. 28, 1950 FOREIGN PATENTS 315,252 Great Britain July10, 1929 376,570 Germany May 30, 1923

